Lecture 4- Intro To Microbiome

Question 1

Exponential growth

Answer 1

Slides 4-7

Question 2

Growing microbes

Answer 2

-grown in either liquid or on/in solid media
*solid medial = agar
*liquid media= broth
-content of the media + the conditions of incubation determine which organisms grow
*microbes are grown in either plates = called Petri dishes/ bottles

Question 3

Plate cultures

Answer 3

*spread plate= sample is spread over the agar surface, bacteria grows on the surface

*pour plate= sample is placed on the plate and agar is poured over it, bacteria grows within the agar

-plates are inverted before incubation
-prevents condensation falling onto plates

Question 4

Culture media

Answer 4

-mix of nutrients in solution
-contain nutrients used by microbes whe grow in laboratory
-contain buffer to maintain pH value
-liquid/ semi sold

Question 5

Agar

Answer 5

-used to make solid media
-rarely used as a nutrient
-remains solid over wide range of incubation conditions
-liquefies at approx 100 degrees, gels at approx 42 degrees
-microbes can be suspended in agar

Question 6

Viable count

Answer 6

-common way of assessing growth of single celled organisms such as bacteria is the viable count

-bacteria are grown on an agar plate; method relies on the fact that one bacteria can produce a colony large enough to be visible

Question 7

Plating methods

Answer 7

Slides 22+ 23

Question 8

Plate count

Answer 8

-each colony is formed from a single bacteria
-by counting the number of colonies= can determine the number of bacteria present
-^assumes microbes are suspended
-expressed as colony forming units; CFUs

Question 9

Dilution

Answer 9

-samples can contain many millions of microbes
-if a plate is inoculated with too many microbes = too many colonies to count
-samples need to be diluted = ensures plates are countable; plates between 30-300 colonies

Question 10

Serial dilution

Answer 10

-used to dilute samples in a consistent manner
-normally in 10 fold steps
-need to know the number of dilutions; to calculate the number of microbes in the original sample

Question 11

Plating

Answer 11

-viable counts can be determined by= pour plates
-number of colonies are counted; plates between 30+300 used

Question 12

The human microbe; intro

Answer 12

-human body; wide range of microorganisms= can have a positive/negative impact on health
-relationship between the microbiome + health; major area of investigation

Question 13

Microbial stains

Answer 13

-every human carries their own which;
*are acquired early in life
*differ between environments and populations
*can persist for years
*undergo relatively rapid transitions

Question 14

Host-microbiota interactions

Answer 14

-microbiome and their host constitute a highly integrated system; holobiont
-undergoes dynamic changes through time as it processes and responds to signals from the environment
*actively modulate development, nutrient absorption and disease onset

Question 15

Normal microbiota

Answer 15

-transient flora may be present for days, weeks or months
*not permanent, form of contamination, potential infection risk & removed by washing
-resident microbiota permanently colonise the host; not removed by washing

Question 16

Normal microbiota

Answer 16

-range of microorganisms
-evolves throughout life
-in a dynamic but stable balance; can be disrupted

Located in; nose + throat, eyes, skin, large intestine and urinary + reproductive systems

-site specific distribution; different bacterial population between diff areas on the body
-develops from birth through childhood

Question 17

Normal microflora

Answer 17

Depends on;
-health
-age
-diet
-climatic conditions

Question 18

Diversity in the human microbiome

Answer 18

-dominated by 4 phyla
*actinobacteria
*bacteriodetes
*firmicutes
*proteobacteria

Question 19

Go through Vevox slides

Answer 19

10-15
32-38